This invention relates to systems and devices for protecting electrical and electronic equipment from the damaging effects of lightning and from other electrical disturbances that are carried to the equipment by external conductors.
Electrical and electronic equipment, particularly electronic equipment using microelectronics, microcircuitry and integrated circuits, are sensitive to electrical surges coming through external electrical conductors such as telephone lines, coaxial cable, digital connections, analog connections, low voltage control lines, and power conductors. These surges may result from lightning strikes or other catastrophic electrical events occurring within the power grid. Various lightning protection devices are available which protect electronic equipment from electrical surges and other undesirable electrical phenomenon. A feature of some of these existing devices is to protect electrical and electronic equipment by disconnecting the equipment from external conductors before any actual surge exists. Generally, the protection devices disconnect the equipment being protected from external conductors in response to a sensor that detects the presence of dangerous atmospheric conditions near the protection device. For example, U.S. Pat. No. 5,453,899 (the xe2x80x9c""899 patentxe2x80x9d) entitled xe2x80x9cLightning Protection Device,xe2x80x9d which is incorporated herein by this reference, discloses a lightning protection device that physically interrupts the electrical connection between electrical and electronic equipment and the power grid when lightning is detected in the vicinity of the equipment by a radio frequency receiver tuned to a frequency that generates a voltage in response to radio frequency static in the general vicinity. U.S. Pat. No. 5,291,208 entitled xe2x80x9cIncipient Lightning Detection and Device Protection,xe2x80x9d which is incorporated herein by this reference, discloses several other detecting mechanisms for sensing electrical activity in the general vicinity of the device.
An important concern with these prior lightning protection devices is that control of the device is typically limited to detection of dangerous atmospheric conditions such as disclosed in the above-referenced patents. Detection of dangerous atmospheric conditions at the precise location of the protection device may not be sufficient to protect the device from damage. For example, some electronic equipment may be located within structures where relevant radio frequencies are difficult to receive. In addition, because electrical storms tend to cover a large geographic area and tend to move quickly, they are very difficult to track based on one geographical data point. Therefore, sensors located on protection devices may not have the range, sensitivity, or accuracy to detect distant atmospheric conditions that may still damage the equipment being protected. Even if more sensitive sensors were employed, such an approach could be cost prohibitive.
Although lightning protection devices may permit users to manually disconnect equipment from external conductors, this is no different than merely unplugging the equipment. Additionally, commercial users of such devices may be inconvenienced by having to have multiples of such units distributed throughout the building to protect a variety of electronic devices. Likewise, a homeowner may be similarly inconvenienced by having to move about an entire house to trigger multiple devices attached to various outlets.
Another important concern with many prior protection devices is that they may not provide adequate insulation between the electrical and electronic equipment being protected and the external conductors carrying the electrical surges. For example, voltages induced in the wiring of a house by a lightning strike may reach or exceed 6,000 volts before the wiring of the house is destroyed. Thus, the insulative capacity of the protection device must be sufficient to prevent a 6,000 volt charge from crossing the insulative barrier and entering the electrical and electronic equipment being protected.
Furthermore, there are additional electrical events that may damage electrical and electronic equipment that are not diminished or mitigated by the use of a conventional lightning protection device. For example, conventional electrical power supplies often suffer from small surges which can damage circuitry but are not sufficient to trigger interruption by the lightning protection device. Moreover, such interruption might not be desirable if the surges are relatively minor and need only to be attenuated. Also, power interruptions may damage electronic equipment.
Surge protectors are available which attenuate minor variations in power supply. Also, uninterruptable power supplies (UPS) are available which continue to provide power to electrical and electronic equipment for some period of time after a power failure, to allow the benign shut-down of the system. Each of these systems are typically provided independent from lightning protection devices, thereby increasing the cost and complexity of the systems required to provide clean, consistent power to the electronic device.
This invention is a lightning protection system for effectively and efficiently protecting electrical and electronic equipment from lightning induced electrical surges and other disturbances. The lightning protection system includes a monitoring system for detecting dangerous atmospheric conditions within specific geographic zones, a transmission system for sending control codes, and multiple circuit connection/disconnection devices for electrically connecting to electrical and electronic equipment to be protected. The lightning protection system protects electrical and electronic equipment by detecting and locating dangerous atmospheric conditions in a particular geographic area and transmitting broadcast control commands to electrical circuit connection/disconnection devices in the geographic area, which have a receiver for receiving the broadcast control commands and an interruption mechanism for disconnecting and reconnecting the electrical equipment from external conductors in response to the control commands. The monitoring system may consist of multiple detectors located in different geographic areas. The monitoring system may also be external to the region receiving the control commands. In the external monitoring system configuration, a centralized monitoring system detects and locates the dangerous atmospheric conditions and transmits this information to the transmission system. The transmission system then transmits control commands to the electrical circuit connection/disconnection devices.
To further enhance the protection of the electrical equipment, the electrical circuit connection/disconnection device may also be controlled in a number of other ways. For example, the electrical circuit connection/disconnection device may be manually operated with the use of a xe2x80x9cstompxe2x80x9d switch, which manually forces the disconnect process. Alternatively, a remote control may be used permitting the user to remotely activate the electrical circuit connection/disconnection device via a hand-held remote control unit, computer, modem, the Internet, wire or wireless telephone, home automation system, or any alternative means of remote communication. In a similar manner, multiple electrical circuit connection/disconnection devices may be connected together in a local area or large area network and controlled in a similar, remote manner. Manual triggering of the electrical circuit connection/disconnection devices may be desirable where certain structures interfere with lightning detection, thus rendering automated disconnection impractical; when normal sources of electrical power have failed; where dangerous, non-lightning related voltages may occur; when a user desires to have the protected equipment powered down; and when peace of mind or convenience dictates disconnection of the protected equipment.
Protection of electrical equipment may be further enhanced by enabling the electrical circuit connection/disconnection device to be controlled by the electrical equipment. Specifically, an electrical circuit connection/disconnection device may have a sensor that detects the status of the on/off switch of the electronic device. When the electrical equipment being protected is turned off, the electrical circuit connection/disconnection device may automatically sever the connection between the electronic equipment and external conductors, thereby insuring that unanticipated electrical surges will not damage the electronic equipment even if the user is not in the vicinity to manually disconnect the device.
In order to provide effective protection of the electrical equipment, the electrical circuit connection/disconnection device may incorporate a disconnect mechanism with substantial insulative capacity. For example, a rotary block with conductive rods passing therethrough may be used to interrupt the external conductors, such as the power supply, modem lines, cable television lines, computer network lines and any other electrical connections, to the electronic equipment. The material used in the insulating rotary block has sufficient insulative characteristics to prevent excessive voltages from crossing the rotary block. Alternatively, the disconnect mechanism may employ a rotating disk with alternating insulating tabs and spaces to interrupt the external conductors from the electronic equipment. The disconnect mechanism may also employ gas-filled or vacuum relays. The gas or vacuum in the relay is sufficiently insulative to prevent excessive voltages from bridging the gap between the relay elements. Alternatively, the disconnect mechanism may employ a substantial gap of air.
Accordingly, it is a feature of this invention to provide a lightning protection system with an accurate, sensitive, and precise detector capable of detecting and locating dangerous atmospheric conditions.
Another feature of the invention is to provide an intelligent lightning protection system that may detect and locate dangerous atmospheric conditions in a specific geographic area and control electrical circuit connection/disconnection devices within the area.
Another feature of the invention is to provide an improved electrical circuit connection/disconnection device for protecting electrical and electronic equipment from various electrical surges that may be controlled by geographically specific radio broadcasts.
Another feature of the invention is to provide an improved electrical circuit connection/disconnection device for protecting electrical and electronic equipment from various electrical surges, which has a disconnect mechanism with sufficient insulative capacity to prevent even extreme voltage surges from crossing the insulative barrier.
A further feature of the invention is to provide an improved electrical circuit connection/disconnection device for protecting electrical and electronic equipment from various electrical surges in combination with other electrical conditioning devices and/or uninterruptable power supplies in a single compact and inexpensive unit.
Another feature of the invention is to provide an electrical circuit connection/disconnection device for protecting electrical and electronic equipment from various electrical surges, which may be controlled manually.
Another feature of the invention is to provide an improved electrical circuit connection/disconnection device for protecting electrical and electronic equipment from various electrical surges, which may be controlled remotely.
Yet another feature of the invention is to provide an improved electrical circuit connection/disconnection device for protecting electrical and electronic equipment from various electrical surges, which may be controlled remotely and in network fashion.